Demand for integrated circuits (ICs) in portable electronic applications has motivated greater levels of semiconductor device integration. Many advanced semiconductor devices in development leverage non-silicon semiconductor materials, including compound semiconductor materials (e.g., GaAs, InP, InGaAs, InAs, and III-N materials). These non-silicon material systems may be employed in high electron mobility transistors (HEMT), some of which may be metal oxide semiconductor field effect transistors (MOSFET).
One technique for fabricating high electron mobility transistors includes forming a non-silicon crystalline device region (e.g., a transistor channel region) over an intermediate supporting structure comprising a material distinct from that of the channel device region and the substrate. Materials for the device region and an underlying sub-structure may form a heterostructure. Even where the heterostructure demarks a boundary between complementary semiconductor materials (e.g., an n-type channel region disposed on a p-type sub-channel region), transistors utilizing the channel region may exhibit relatively poor short channel effect (SCE). Device architectures that further reduced SCE in such devices are therefore desirable.